Racer X <[EMAIL PROTECTED]> writes:
> Not true. Blocking port 25 benefits the customer as well:
> * It makes it far less likely that your dialup pool (or, for that
> matter, your whole net block) will end up in a blackhole list somewhere.
This is not a benefit to the customer who doesn't want to send out mail
themselves, since if they're not sending out mail directly, what do they
care whether people drop mail from that dialup pool? So you're increasing
the chances that they can send mail from the dialup pool by eliminating
their ability to send mail from the dialup pool.
I don't see the benefit. Maybe you're talking about people who blackhole
netblocks for all traffic just because they're getting e-mail spam from
it? I suppose that there's some marginal benefit in increasing your
customer's ability to contact stupid people.
> * It takes a lot less time and effort to figure out when someone is
> spamming and who they are, since everything is occurring on your mail
> server.
This is not a benefit to the customer.
> * It allows the ISP to take a pro-active role in spam prevention. It's
> fairly simple to write a shell script that checks the mail queue every
> few minutes, or sees how many connections occurred, and send an alert
> based on that.
This is not a benefit to the customer.
> All of these measures benefit the customers as much as the admins, in
> terms of the savings in time and resources needed to deal with spam.
No, they don't. They benefit the admins in the amount of time and energy
they have to spend dealing with outgoing spam, something that in a
well-run ISP the legitimate customers of the ISP should never notice.
Don't fool yourself. The benefit to the customer in blocking port 25
outbound is basically nonexistent; it's entirely about administrative
resources devoted to keeping one's site from abusing the Internet. It may
be necessary, but you can't sell it as a feature.
--
Russ Allbery ([EMAIL PROTECTED]) <URL:http://www.eyrie.org/~eagle/>
